sp-std removal from substrate/primitives (#3274)

This PR removes sp-std crate from substrate/primitives sub-directories.

For now crates that have `pub use` of sp-std or export macros that would
necessitate users of the macros to `extern crate alloc` have been
excluded from this PR.

There should be no breaking changes in this PR.

---------

Co-authored-by: Koute <koute@users.noreply.github.com>

substrate/primitives/trie/src/trie_stream.rs

@@ -21,9 +21,9 @@ use crate::{
 	node_header::{size_and_prefix_iterator, NodeKind},
 	trie_constants,
 };
+use alloc::vec::Vec;
 use codec::{Compact, Encode};
 use hash_db::Hasher;
-use sp_std::vec::Vec;
 use trie_root;
 
 /// Codec-flavored TrieStream.